Notational Conventions
iv
-
In syntax descriptions, the instruction, command, or directive is in bold
typeface and parameters are in an
italic typeface. Portions of a syntax that
are in bold must be entered as shown; portions of a syntax that are in
italics
describe the type of information that must be entered. Here is an example
of a directive syntax:
.asect
”
section name”, address
The directive .asect has two parameters, indicated by
section name and
address. When you use .asect, the first parameter is an actual section
name, enclosed in double quotes; the second parameter is an address.
-
Square brackets ( [ and ] ) identify an optional parameter. If you use an
optional parameter, you specify the information within the brackets; you
do not enter the brackets themselves. Here is an example of an instruction
that has an optional parameter:
LALK
16-bit constant [, shift]
The LALK instruction has two parameters. The first parameter,
16-bit
constant, is required. The second parameter, shift, is optional. As this syntax
shows, if you use the optional second parameter, you must precede it with a
comma.
Square brackets are also used as part of the pathname specification for
VMS pathnames; in this case, the brackets are actually part of the path-
name (they are not optional).
-
Braces ( { and } ) indicate a list. The symbol | (read as
or) separates items
within the list. Here is an example of a list:
{ * | *+ | *– }
This provides three choices:
*
,
*+
, or
*–
.
Unless the list is enclosed in square brackets, you must choose one item
from the list.
-
Some directives can have a varying number of parameters. For example,
the .byte directive can have up to 100 parameters. The syntax for this direc-
tive is:
.byte
value
1
[, ... , value
n
]
This syntax shows that .byte has at least one value parameter, but you
may supply additional value parameters, separated by commas.
